i3c: master: renesas: Fix memory leak in renesas_i3c_i3c_xfers()

In the Linux kernel, the following vulnerability has been resolved:

i3c: master: renesas: Fix memory leak in renesas_i3c_i3c_xfers()

The xfer structure allocated by renesas_i3c_alloc_xfer() was never freed in the renesas_i3c_i3c_xfers() function. Use the __free(kfree) cleanup attribute to automatically free the memory when the variable goes out of scope.